<% define_content :link do -%>
  <%= polymorphic_url([asset.submission.assignment.context, asset.submission.assignment, :submission], id: asset.submission.user) %>
<% end -%>
<%= t :tweet, "Canvas Alert - Comment: %{author} for %{assignment}, %{user}, %{context}.", 
        :author => asset.author.name, 
        :assignment => asset.submission.assignment.title, 
        :user => asset.submission.user.name, 
        :context => asset.submission.assignment.context.name %>